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Real Time Kinematic (RTK) is a land surveying technique based on carrier phase measurements with a single reference station or a network of reference stations providing real time corrections to a mobile receiver. In RTK applications, sending corrections to mobile units in an area is a demanding expensive task with different approaches, proposed mainly by Leica and GEO++ and Trimble (MAC or Master Auxilary Concept & VRS or Virtual Reference Stations). Precise Point Positioning PPP is a different newly developed approach which uses only measurements from one receiver, making the reference station obsolete. PPP allows determining coordinates with a similar precision as conventional RTK approaches. However, in order to achieve a similar precision, precise orbit and satellite clock information is needed which are provided by IGS. The major disadvantage of this new approach is the long integration time needed in order to reach a cm to dm-level accuracy. This is due to the fact that the ambiguities are considered as real values in the estimation, compared to the RTK where they are fixed to the corresponding integer values. Two existing elements in the phase measurements are satellite and receiver phase biases. These elements cause the ambiguity to have a real value. The goal in this project is to reduce the integration time by modeling these elements, so the PPP would become a tool for Real time Positioning. Omid Kamali, étudiant au doctorat
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